Teaching of dimensional, mathematical, and other incremental relationships, such as temperature scales, logarithmic scales and the like, to groups of students in a classroom environment often has created difficulties, both from the instructor's ability to easily demonstrate visually the information he is attempting to convey and the ability of the student to see and understand such visual information. Rulers, temperature scales, and other incrementally graduated scales generally are small in size and the graduations on the scale are so minute that the instructor often can effectively demonstrate the use of the scale to only one or two students at a time. In an effort to satisfy these problems, Johannsen U.S. Pat. No. 4,842,521 discloses a visual aid ruler that includes an enlarged ruler scale and a selectively adjustable pointer to facilitate teaching use of the scale. The effectiveness of the ruler, however, is limited. The ruler is not adapted for easily teaching mathematical relationships, such as addition, subtraction, and multiplication, and use of the ruler is limited to the particular scale depicted on the face thereof.